In the prior art, there are mainly two ways for switching between a Transport Video Interface output signal (TVI) and a Composite Video Broadcast Signal or Composite Video Blanking and Sync (CVBS), one is a switching method with a dial switch inside a camera, the other is a cable overlapping of camera outgoing lines.
In the first switching method with a dial switch, the output switching between the TVI and CVBS is performed by a dial switch, the dial switch is generally arranged on a PCB (printed circuit board) inside the camera, and when the output is required to be switched, the corresponding BNC cable is connected to a digital video recorder (DVR), then the machine shell is opened, and the dial switch is shifted to a corresponding position, so that switching is realized; the disadvantages of the method are that the operation of opening the machine shell is relatively troublesome, and the size of the dial switch is relatively large, which occupies a relatively large PCB space. Furthermore, there is certain interference on the structure, which is not beneficial to user operation. FIG. 1 is a schematic diagram of a video signal switching method in the prior art. As shown in FIG. 1, the switching is realized manually by a dial switch installed in a camera. In FIG. 1, the first cable is a cable for transmitting a composite video broadcast signal CVBS, and the second cable is a cable for transmitting a transport video interface output signal TVI.
In the second switching method with cable overlapping, the output switching between the TVI and CVBS is realized by two control lines led out by an overlapping machine, wherein one signal is output by default, and the other signal is output when the cable is overlapped. The disadvantages of the method are that the led and exposed cable is easy to bring static electricity and other problems, and the twisted cable may cause mechanical fatigue and be also easily affected by external forces to cause loose contact, affecting the use of the machine. FIG. 2 is a schematic diagram of another video signal switching method in the prior art. As shown in FIG. 2, two overlapping wire 1 and wire 2 are led out at one side of the camera, and the overlapping wires are connected to the DVR through selection, and then the TVI and the CVBS signal lines are overlapped on the DVR to realize signal switching. In FIG. 2, the first cable is a cable for transmitting a composite video broadcast signal CVBS, and the second cable is a cable for transmitting a transport video interface output signal TVI.
For the above problems, no effective solution has been proposed yet.